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Sep 20, 2013
09/13

by
Adam F. Falk

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These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic $B$ decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed.

Source: http://arxiv.org/abs/hep-ph/9610363v1

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Sep 20, 2013
09/13

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Adam F. Falk

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I suggest that the conventional assignment of quantum numbers to the observed charm and bottom baryons is not correct, as these assignments imply large violation of the heavy spin-flavor and light $SU(3)$ symmetries. I propose an alternative interpretation of the observed states, in which the symmetries are preserved. If these novel assignments are right, there is a new state with mass approximately 2380~MeV which decays to $\Lambda_c+\gamma$, and another with mass approximately 5760~MeV which...

Source: http://arxiv.org/abs/hep-ph/9603389v2

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Sep 22, 2013
09/13

by
Adam F. Falk

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We consider the effects of excited states on the $SU(3)$ breaking chiral loop corrections to heavy meson properties. In particular, we compare the size of kaon loops in which an excited heavy meson appears to the size of previously calculated loops with heavy mesons in the ground state. We find that the new effects may indeed be of the same magnitude as the old ones, but that there is a strong dependence on the unknown masses and coupling constants of the new states. As a result, we argue that...

Source: http://arxiv.org/abs/hep-ph/9302265v1

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Sep 17, 2013
09/13

by
Adam F. Falk

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These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. The use of heavy quark methods for the extraction of |V_cb| and |V_ub| is presented is some detail.

Source: http://arxiv.org/abs/hep-ph/0007339v1

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Sep 21, 2013
09/13

by
Adam F. Falk

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I discuss a variety of issues in the physics of excited bottom and charmed hadrons. Recent developments in spectroscopy, strong decays, and production in fragmentation and weak decays are reviewed.

Source: http://arxiv.org/abs/hep-ph/9609380v1

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Sep 19, 2013
09/13

by
Adam F. Falk

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An overview of the theory of B physics is given, with an emphasis on issues in the strong interactions and hadronic physics. This article is taken from an introductory chapter of The BaBar Physics Book - Physics at an Asymmetric B Factory, SLAC Report SLAC-R-504. It is written at the level of a basic survey aimed at the experimental community.

Source: http://arxiv.org/abs/hep-ph/9812217v1

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Jul 20, 2013
07/13

by
Adam F. Falk

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I review the use of the Heavy Quark Effective Theory in the computation of total rates and differential kinematic distributions in inclusive semileptonic and radiative B decays. Particular attention is paid to strategies for the extraction of V_{cb} and V_{ub}.

Source: http://arxiv.org/abs/hep-ph/9712364v1

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Sep 23, 2013
09/13

by
Adam F. Falk

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A review is given of recent developments in the physics of flavor. Current constraints on the Cabibbo-Kobayashi-Maskawa matrix are discussed and related to the recent measurements of epsilon'/epsilon, sin(2beta) and K+ -> pi+ nu nubar. A brief review is given of the connection between CP violation in B decays and electroweak baryogenesis. Finally, there is an extensive discussion of how present and proposed experiments in K and B physics can constrain the pattern of flavor changing processes...

Source: http://arxiv.org/abs/hep-ph/9908520v4

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Sep 22, 2013
09/13

by
Adam F. Falk

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I discuss the recent controversy over the semileptonic branching ratio of the $B$ meson, pointing out that it is only the combination of this quantity with the reported charm multiplicity in $B$ decays which is in serious conflict with theoretical calculations. I consider possible solutions to the problem. (Invited talk presented at the Eighteenth Johns Hopkins Workshop on Current Problems in Particle Theory, Florence, Italy, August 31--September 2, 1994.)

Source: http://arxiv.org/abs/hep-ph/9410312v3

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Sep 23, 2013
09/13

by
Adam F. Falk

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Recent developments in the theory of heavy quarks are reviewed. In the area of heavy quark fragmentation, there has been progress in the study of both pertubative and nonperturbative processes, including the identification of new observable nonperturbative fragmentation parameters. There has also been considerable theoretical activity in the study of inclusive rare and semileptonic decays of bottom hadrons.

Source: http://arxiv.org/abs/hep-ph/9310360v2

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Sep 21, 2013
09/13

by
Adam F. Falk

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I review the recent proposal that there are new isotriplet heavy baryons with masses approximately 2380 MeV and 5760 MeV. This prediction follows from the application of heavy spin-flavor and light $SU(3)$ symmetries to the observed charmed and bottom baryon states. It also entails assumptions about the spin and parity quantum numbers of the observed states which are different than is commonly supposed. The discovery of such states would imply that the nonrelativistic constituent quark model is...

Source: http://arxiv.org/abs/hep-ph/9609208v2

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Jul 20, 2013
07/13

by
Adam F. Falk

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We explore the possibility of measuring the CKM parameter gamma using CP tagged decays at a very high luminosity e+e- B Factory. A new collider capable of integrating as much as 10 inverse attobarns per year is being discussed as a possible future for SLAC beyond the current PEP-II program, and could also be in the future of KEK. In two years of operation, it could be possible for a successor to BaBar or Belle to accumulate a sample of one million CP tagged B decays. We find that a...

Source: http://arxiv.org/abs/hep-ph/0107066v2

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Sep 22, 2013
09/13

by
Adam F. Falk

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I review the current status of our knowledge of CP violation and flavor physics. I discuss where one should look for future improvements, and outline the experimental and theoretical priorities of the field.

Source: http://arxiv.org/abs/hep-ph/0201094v3

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Sep 23, 2013
09/13

by
Adam F. Falk

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I discuss the effect of final state interactions on the determination of the CKM angle \gamma from B -> K + pi decays. Using a simple Regge-based model for rescattering processes, I argue that such effects could be substantial enough to make it problematic to obtain reliable limits on \gamma in this way. Fortunately, an analysis of B -> K + K decays may provide model-independent bounds on rescattering contributions.

Source: http://arxiv.org/abs/hep-ph/9806538v1

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Sep 22, 2013
09/13

by
Adam F. Falk

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Theoretical aspects of rare $B$ decays are reviewed. The focus is on the relation between short-distance interactions and physical observables. It is argued that there remain significant uncertainties in the theoretical treatment of certain important quantities. (Talk presented at the International Symposium on Vector Boson Interactions, University of California, Los Angeles, February 1-3, 1995)

Source: http://arxiv.org/abs/hep-ph/9503485v1

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Sep 22, 2013
09/13

by
Adam F. Falk

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I discuss the theory of heavy baryon spectroscopy, emphasizing predictions which follow from light and heavy quark symmetries.

Source: http://arxiv.org/abs/hep-ph/9707295v1

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Sep 22, 2013
09/13

by
Adam F. Falk; Matthias Neubert

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In the heavy quark effective theory, hadronic matrix elements of currents between two hadrons containing a heavy quark are expanded in inverse powers of the heavy quark masses, with coefficients that are functions of the kinematic variable $v\cdot v'$. For the ground state pseudoscalar and vector mesons, this expansion is constructed at order $1/m_Q^2$. A minimal set of universal form factors is defined in terms of matrix elements of higher dimension operators in the effective theory. The zero...

Source: http://arxiv.org/abs/hep-ph/9209268v1

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Sep 22, 2013
09/13

by
Adam F. Falk; Benjamin Grinstein

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The combined use of chiral $SU(3)$ and heavy quark symmetries allows one to relate the hadronic form factors for the decay $\bar B\to \bar K\e^+\e^-$ to those for $\bar B\to\pi\e^-\bar\nu$. We investigate departures from the symmetry limit which arise from chiral symmetry breaking. The analysis uses chiral perturbation theory and the heavy quark limit to compute the relevant hadronic matrix elements. We estimate the size of $SU(3)$ corrections by computing, at one loop order, the leading...

Source: http://arxiv.org/abs/hep-ph/9306310v1

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Jul 20, 2013
07/13

by
Adam F. Falk; Michael Luke

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We construct an effective Lagrangian describing the interaction of soft pions and kaons with mesons containing a heavy quark and light degrees of freedom in an orbital $p$ wave. The formalism is easily extended to heavy mesons and baryons in arbitrary excited states. We calculate the leading contributions to the strong decays $\dtwo\to\d\pi$, $\dtwo\to\dstar\pi$ and $\done\to\dstar\pi$. We confirm the relations between the rates previously obtained by Isgur and Wise using heavy quark symmetry,...

Source: http://arxiv.org/abs/hep-ph/9206241v1

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Sep 22, 2013
09/13

by
Adam F. Falk; Matthias Neubert

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The analysis of $1/m_Q^2$ corrections of the previous paper is extended to the semileptonic decays of heavy baryons. We focus on the simplest case, the ground state $\Lambda_Q$ baryons, in which the light degrees of freedom are in a state of zero total angular momentum. The formalism, while identical in spirit, is considerably less cumbersome than for heavy mesons. The general results are applied to the semileptonic decay $\Lambda_b\to\Lambda_c\,\ell\,\nu$. An estimate of the leading power...

Source: http://arxiv.org/abs/hep-ph/9209269v1

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Sep 22, 2013
09/13

by
George Chiladze; Adam F. Falk

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The CLEO Collaboration recently has announced the discovery of an excited charmed and strange baryon. We estimate the expected width of this new member of the Xi_c family. We discuss the phenomenology of the excited csq and css states, and consider what additional charmed baryons might be observable in the future. We point out that the final state Xi_c + K could be an interesting new channel to examine.

Source: http://arxiv.org/abs/hep-ph/9707507v2

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Sep 22, 2013
09/13

by
Adam F. Falk; Michael Luke

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We compute the first two moments of the final hadronic invariant mass in inclusive semileptonic B decay, in the presence of a cut on the charged lepton energy. These moments may be measured directly by experiments at the Upsilon(4S) using the neutrino reconstruction technique, which requires such a cut. Measurement of these moments will place constraints on the nonperturbative parameters \bar\Lambda and \lambda_1, which are relevant for extracting the quark masses m_b and m_c, as well as the...

Source: http://arxiv.org/abs/hep-ph/9708327v1

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Sep 20, 2013
09/13

by
Adam F. Falk; Thomas Mehen

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We examine the decays of excited heavy mesons, including the leading power corrections to the heavy quark limit. We find a new and natural explanation for the large deviation of the width of the $D_1(2420)$ from the heavy quark symmetry prediction. Our formalism leads to detailed predictions for the properties of the excited bottom mesons, some of which recently have been observed. Finally, we present a detailed analysis of the effect of power corrections and finite meson widths on the angular...

Source: http://arxiv.org/abs/hep-ph/9507311v1

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Sep 20, 2013
09/13

by
Adam F. Falk; Michael E. Peskin

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We discuss the production via fragmentation of excited heavy mesons and baryons, and their subsequent decay. In particular, we consider the question of whether a net polarization of the initial heavy quark may be detected, either in a polarization of the final ground state or in anisotropies in the decay products of the excited hadron. The result hinges in part on a nonperturbative parameter which measures the net transverse alignment of the light degrees of freedom in the fragmentation...

Source: http://arxiv.org/abs/hep-ph/9308241v1

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Sep 18, 2013
09/13

by
Adam F. Falk; Alexey A. Petrov

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We propose a novel method of measuring the CKM matrix element V_ub, via inclusive B decays to "wrong sign" charm. This process is mediated by the quark level decay b -> u cbar s'. When normalized to the inclusive semileptonic decay rate, the theoretical expression is very well behaved, with small uncertainties from unknown quark masses and no leading renormalon ambiguity. We compute the decay rate for this process, including the leading perturbative and nonperturbative corrections.

Source: http://arxiv.org/abs/hep-ph/9903518v3

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Sep 21, 2013
09/13

by
Adam F. Falk; Matthias Neubert; Michael Luke

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We reformulate the heavy quark effective theory in the presence of a residual mass term, which has been taken to vanish in previous analyses. While such a convention is permitted, the inclusion of a residual mass allows us to resolve a potential ambiguity in the choice of the expansion parameter which defines the effective theory. We show to subleading order in the mass expansion that physical quantities computed in the effective theory do not depend on the expansion parameter.

Source: http://arxiv.org/abs/hep-ph/9204229v1

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Sep 20, 2013
09/13

by
Michael Booth; George Chiladze; Adam F. Falk

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We develop quenched chiral perturbation theory for vector mesons made of light quarks, in the limit where the vector meson masses are much larger than the pion mass. We use this theory to extract the leading nonanalytic dependence of the vector meson masses on the masses of the light quarks. By comparing with analogous quantities computed in ordinary chiral perturbation theory, we estimate the size of quenching effects, observing that in general they can be quite large. This estimate is...

Source: http://arxiv.org/abs/hep-ph/9610532v1

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Sep 19, 2013
09/13

by
Jonathan A. Bagger; Adam F. Falk

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The supersymmetric analog of the Goldberger-Treiman relation plays a critical role in the low energy effective theory of models in which supersymmetry is spontaneously broken in a hidden sector. The interactions that connect the hidden and visible sectors break a global symmetry, which implies that the low energy theory must be constructed consistently in inverse powers of the messenger scale. The Goldberger-Treiman relation determines the couplings of the Goldstino to the visible sector...

Source: http://arxiv.org/abs/0708.3364v1

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Sep 18, 2013
09/13

by
Christian Bauer; Adam F. Falk; Michael Luke

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We study logarithms of the form $\ln(m_q/m_b)$ which arise in the inclusive semileptonic decay of a bottom quark to a quark of mass $m_q$. We use the renormalization group to resum the leading radiative corrections to these terms, of the form $m_q^2\alpha_s^n\ln^n(m_q/m_b)$, $m_q^3\alpha_s^{n+1}\ln^n(m_q/m_b)$ and $m_q^4\alpha_s^n\ln^{n+1}(m_q/m_b)$. The first two resummations are trivial, while the latter involves a non-trivial mixing of four-fermi operators in the $1/m_b$ expansion. We...

Source: http://arxiv.org/abs/hep-ph/9604290v2

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Sep 22, 2013
09/13

by
Adam F. Falk; Alexey A. Petrov

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We propose a new method for measuring the CKM phase gamma using the partial rates for CP-tagged Bs decays. Such an experiment could be performed at a very high luminosity symmetric e+e- collider operating at the Upsilon(5S) resonance, where the Bs-Bsbar state is produced in a state of definite CP. We also discuss CP-tagging in the Bd system at the Upsilon(4S), where a time-dependent analysis is required to compensate for the anticipated large CP violation in Bd-Bdbar mixing.

Source: http://arxiv.org/abs/hep-ph/0003321v1

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Sep 18, 2013
09/13

by
George Chiladze; Adam F. Falk; Alexey A. Petrov

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The recent discovery of the B_c meson by the CDF collaboration and proposed new experiments at Fermilab and CERN motivate new theoretical studies of the B_c system. Here we investigate the radiative leptonic decay B_c -> gamma l nu. This process is an important background to the annihilation process B_c -> l nu, which will be used to extract the B_c decay constant. We perform a model-independent calculation, based on QCD, of the partial width and various kinematic distributions. We also...

Source: http://arxiv.org/abs/hep-ph/9811405v2

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Sep 23, 2013
09/13

by
Adam F. Falk; Michael Luke; Mark B. Wise

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We reconsider the recent derivation by de Rafael and Taron of bounds on the slope of the Isgur-Wise function. We argue that one must be careful to include cuts starting below the heavy meson pair production threshold, arising from heavy quark-antiquark bound states, and that if such cuts are properly accounted for then no constraints may be derived.

Source: http://arxiv.org/abs/hep-ph/9211222v1

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Sep 22, 2013
09/13

by
Adam F. Falk; Zoltan Ligeti; Yosef Nir; Helen Quinn

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Recent experimental results on $B\to\rho\rho$ decays indicate that the CP asymmetry $S_{\rho^+\rho^-}$ will give an interesting determination of $\alpha=\arg[-(V_{td}V_{tb}^*)/(V_{ud}V_{ub}^*)]$. In the limit when the $\rho$ width is neglected, the $B\to\pi\pi$ isospin analysis can also be applied to $B\to\rho\rho$, once an angular analysis is used to separate transversity modes. The present bound on the shift of $S_{\rho^+\rho^-}$ from the true $\sin2\alpha$ is already stronger than it is for...

Source: http://arxiv.org/abs/hep-ph/0310242v2

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Jul 19, 2013
07/13

by
Adam F. Falk; Zoltan Ligeti; Matthias Neubert; Yosef Nir

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We calculate the differential decay rate for inclusive $\bar B\to\tau\,\bar\nu\,X$ transitions to order $1/m_b^2$ in the heavy quark expansion, for both polarized and unpolarized tau leptons. We show that using a systematic $1/m_b$ expansion significantly reduces the theoretical uncertainties in the calculation. We obtain for the total branching ratio ${\rm BR}(\bar B\to\tau\,\bar\nu\,X)=2.30\pm 0.25\%$, and for the tau polarization $A_{\rm pol}=-0.706\pm0.006$. {}From the experimental...

Source: http://arxiv.org/abs/hep-ph/9401226v1

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Sep 19, 2013
09/13

by
Adam F. Falk; Mark B. Wise; Isard Dunietz

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We reconsider the conflict between recent calculations of the semileptonic branching ratio of the $B$ meson and the experimentally measured rate. Such calculations depend crucially on the application of ``local duality'' in nonleptonic decays, and we discuss the relation of this assumption to the weaker assumptions required to compute the semileptonic decay rate. We suggest that the discrepancy between theory and experiment might be due to the channel with two charm quarks in the final state,...

Source: http://arxiv.org/abs/hep-ph/9405346v2

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Jul 19, 2013
07/13

by
Lee Brekke; Hans Dykstra; Adam F. Falk; Tom D. Imbo

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We study the statistics of vortices which appear in (2+1)--dimensional spontaneously broken gauge theories, where a compact group G breaks to a finite nonabelian subgroup H. Two simple models are presented. In the first, a quantum state which is symmetric under the interchange of a pair of indistinguishable vortices can be transformed into an antisymmetric state after the passage through the system of a third vortex with an appropriate $H$-flux element. Further, there exist states containing...

Source: http://arxiv.org/abs/hep-th/9210131v1

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Sep 20, 2013
09/13

by
Adam F. Falk; Michael Luke; Martin J. Savage

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We discuss nonperturbative contributions to the inclusive rare $B$ decays $B\to X_s\gamma$ and $B\to X_s\ell^+\ell^-$. We employ an operator product expansion and the heavy quark effective theory to compute the leading corrections to the decay rate found in the free quark decay model, which is exact in the limit $m_b\to\infty$. These corrections are of relative order $1/m_b^2$, and may be parameterised in terms of two low-energy parameters. We also discuss the corrections to other observables,...

Source: http://arxiv.org/abs/hep-ph/9308288v1

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Sep 23, 2013
09/13

by
Adam F. Falk; Michael Luke; Martin J. Savage

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We apply a recent theoretical analysis of hadronic observables in inclusive semileptonic heavy hadron decays to the phenomenology of $B$ and $D$ mesons. Correlated bounds on the nonperturbative parameters $\bar\Lambda$ and $\lambda_1$ are derived by considering data from $B$ decays and, independently, data from $D$ decays. The two sets of bounds are found to be consistent with each other. The data from $B$ decays are then are used to extract a lower limit on the CKM matrix element $|V_{cb}|$....

Source: http://arxiv.org/abs/hep-ph/9511454v3

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Sep 21, 2013
09/13

by
Junegone Chay; Adam F. Falk; Michael Luke; Alexey A. Petrov

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We explore the theoretical feasibility of extracting V_ub from two ratios built from B meson inclusive partial decays, R_1 = Gamma(b-> u cbar s)/3Gamma(b -> c l nu), and R_2 = [Gamma(b -> c X) - Gamma(b -> cbar X)]/Gamma(b -> c ubar d). We discuss contributions to these quantities from perturbative and nonperturbative physics, and show that they can be computed with overall uncertainties at the level of 10%.

Source: http://arxiv.org/abs/hep-ph/9907363v1

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Sep 20, 2013
09/13

by
Adam F. Falk; Michael Luke; Martin J. Savage

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We calculate the leading perturbative and power corrections to the hadronic invariant mass and energy spectra in semileptonic heavy hadron decays. We apply our results to the $B$ system. Moments of the invariant mass spectrum, which vanish in the parton model, probe gluon bremsstrahlung and nonperturbative effects. Combining our results with recent data on $B$ meson branching ratios, we obtain a lower bound $\bar\Lambda>410\,{\rm MeV}$ and an upper bound $m_b^{\rm pole}

Source: http://arxiv.org/abs/hep-ph/9507284v2

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Sep 18, 2013
09/13

by
Adam F. Falk; Yuval Grossman; Zoltan Ligeti; Alexey A. Petrov

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The main challenge in the Standard Model calculation of the mass and width difference in the D0-D0bar system is to estimate the size of SU(3) breaking effects. We prove that D meson mixing occurs in the Standard Model only at second order in SU(3) violation. We consider the possibility that phase space effects may be the dominant source of SU(3) breaking. We find that y=(Delta Gamma)/(2Gamma) of the order of one percent is natural in the Standard Model, potentially reducing the sensitivity to...

Source: http://arxiv.org/abs/hep-ph/0110317v2

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Sep 21, 2013
09/13

by
Adam F. Falk; Zoltan Ligeti; Mark B. Wise

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The hadronic invariant mass spectrum for the inclusive charmless semileptonic decay $B\to X_u e \bar\nu_e$ is studied. Particular attention is paid to the region $s_H

Source: http://arxiv.org/abs/hep-ph/9705235v1

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Sep 19, 2013
09/13

by
George Chiladze; Adam F. Falk; Alexey A. Petrov

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We study the production of charmonium hybrids in B decays. We use the operator product expansion and nonrelativistic QCD to organize the various contributions to this process. We express the decay rate in terms of a few matrix elements which eventually will be fixed by experimental measurements or calculated on the lattice. While the Fock state expansion is problematic for hybrids, in that there is no perturbative large mass limit, the operator product expansion still provides a model...

Source: http://arxiv.org/abs/hep-ph/9804248v1

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Sep 23, 2013
09/13

by
Jonathan A. Bagger; Adam F. Falk; Morris Swartz

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We compute the bounds from precision observables on alternative theories of electroweak symmetry breaking. We show that a cut-off as large as 3 TeV can be accomodated by the present data, without unnatural fine tuning.

Source: http://arxiv.org/abs/hep-ph/9908327v2

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Sep 19, 2013
09/13

by
Adam F. Falk; Yosef Nir; Alexey A. Petrov

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We argue that there could be large, SU(3) violating resonance contributions to D -> K pi decays which would affect the extraction of the D0-anti-D0 mixing parameters from experiment. Such contributions can induce a large strong phase in the interference between the doubly Cabibbo suppressed and the mixing induced Cabibbo favored contributions to the D0 -> K^+ pi^- and anti-D0 -> K^- pi^+ decays. Consequently, the interpretation of a large, CP conserving interference term can involve a...

Source: http://arxiv.org/abs/hep-ph/9911369v2

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Sep 18, 2013
09/13

by
Adam F. Falk; Adam Lewandowski; Alexey A. Petrov

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We consider contributions to the rare decay K+ -> pi+ nu nubar which become nonlocal at the charm scale. Compared to the leading term, such amplitudes are suppressed by two powers of mK/mc and could potentially give corrections at the level of 15%. We compute the leading coefficients of the subleading dimension eight operators in the effective theory below the charm mass. The matrix elements of these operators cannot all be calculated from first principles and some must be modeled. We find...

Source: http://arxiv.org/abs/hep-ph/0012099v2

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Sep 19, 2013
09/13

by
Isard Dunietz; Peter S. Cooper; Adam F. Falk; Mark B. Wise

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It is usually assumed that the production of baryons in $B$ meson decays is induced primarily by the quark level process $b\to c\bar ud$, where the charm quark hadronizes into a charmed baryon. With this assumption, the $\Lambda_c$ momentum spectrum would indicate that the transition $B\to\Lambda_c X$ is dominated by multi-body $B$ decays. However, a closer examination of the momentum spectrum reveals that the mass $m_X$ against which the $\Lambda_c$ is recoiling almost always satisfies...

Source: http://arxiv.org/abs/hep-ph/9405347v1

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Sep 19, 2013
09/13

by
Andrew E. Blechman; Adam F. Falk; Dan Pirjol; John M. Yelton

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Motivated by recent results on charmed baryons from CLEO and FOCUS, we reexamine the couplings of the orbitally excited charmed baryons. Due to its proximity to the [Sigma_c pi] threshold, the strong decays of the Lambda_c(2593) are sensitive to finite width effects. This distorts the shape of the invariant mass spectrum in Lambda_{c1}-> Lambda_c pi^+pi^- from a simple Breit-Wigner resonance, which has implications for the experimental extraction of the Lambda_c(2593) mass and couplings. We...

Source: http://arxiv.org/abs/hep-ph/0302040v1

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Sep 21, 2013
09/13

by
Adam F. Falk; Yuval Grossman; Zoltan Ligeti; Yosef Nir; Alexey A. Petrov

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We study the Standard Model prediction for the mass difference between the two neutral D meson mass eigenstates, $\Delta m$. We derive a dispersion relation based on heavy quark effective theory that relates $\Delta m$ to an integral of the width difference of heavy mesons, $\Delta\Gamma$, over varying values of the heavy meson mass. Modeling the $m_D$-dependence of certain D decay partial widths, we investigate the effects of SU(3) breaking from phase space on the mass difference. We find that...

Source: http://arxiv.org/abs/hep-ph/0402204v1

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Sep 21, 2013
09/13

by
Adam F. Falk; Michael Luke; Martin J. Savage; Mark B. Wise

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We discuss the fragmentation of a heavy quark to a baryon containing two heavy quarks of mass $m_Q\gg\Lambda_{\rm QCD}$. In this limit the heavy quarks first combine perturbatively into a compact diquark with a radius small compared to $1/\Lambda_{\rm QCD}$, which interacts with the light hadronic degrees of freedom exactly as does a heavy antiquark. The subsequent evolution of this $QQ$ diquark to a $QQq$ baryon is identical to the fragmentation of a heavy antiquark to a meson. We apply this...

Source: http://arxiv.org/abs/hep-ph/9305315v1